Method of making bearings



Dec. 29, 1936. BROWNBACK 2,066,247

METHOD OF MAKING BEARINGS Filed Jan. 9, 1955 Patented Dec. 29, 1936 UNITED STATES PATENT OFFICE METHOD OF MAKING BEARINGS Henry Lowe Brownback, Norrlstown, Pa.

Application January 9, 1935, Serial No, 1,049

5 Claims.

This invention relates primarily to bearings particularly for use in gasoline and other internal combustion engines, and the principal object thereof is to provide a novel bearing'and method of making same, the bearing consisting of lining steel or ferrous shells with bronze, copper, copper-lead mixtures, or brass, my novel method involving a step in which the molten copper of the bronze or brass (or a molten copper film alone) is permitted to soak into the heated steel or ferrous shell for a suflicient length of time to permit penetration thereof an appreciable distance into the steel shell and to form on the shell a surface copper-iron alloy bonded with the steel, to which alloy the bronze or brass which forms the material of the bearing lining will subsequently readily unite, thereby providing a novel bearing having a decidedly better bond between the shell and lining, the lining in fact havingpenetrated and alloyed with the surface of the steel shell in much the same manner as carbon in case-hardening processes.

In most cases the lining of steel shells with bronzes or brasses and particularly copper-lead mixtures high in lead has heretofore been accomplished by heating the steel shell in a nonoxidizing atmosphere to a temperature considerably higher than the melting point of the bronze, and by heating the bronze to a temperature higher than its normal melting.point, and then removing the shell from the furnace, adding a flux, and pouring the bronze in the shell. As soon as this is done the piece is cooled quickly or quenched to avoid precipitation of the lead. As the copper of the lining is in contact with the steel for only a short time interval the penetration is very slight, and moreover the copper has a tendency to oxidize during pouring. The flux, if used in excess, also causes trouble.

Another process heretofore used consisted of putting bronze in a shell which was sealed at both ends and which contained a volatile flux.

The shell was then placed in a furnace and heated until the bronze became liquid, after which time it was placed in a machine and centrifuged into contact with the walls of the shell. In this process the bronze likewise came into contact with the heated steel for only a short interval of time as the shell was necessarily quenched just as soon as the bronze was distributed as otherwise the lead would be also centrifuged into contact with the steel shell destroying the bond. This process .was limited to the use of alloys fairly low in lead for the reason stated.

In my process the bronze or brass and the shell is preferably placed in a crucible of the type shown in my French Patent No. 747,334, sealed at both ends except for a small vent hole, and the shell or tube charged into a furnace. If the furnace has a non-oxidizing or reducing atmosphere it is not necessary to add a volatile de-oxidant in the crucible, shell, or other part to be coated, but if the furnace is of the ordinary combustion type a volatile chemical should be added to be volatilized by the furnace heat and displace the air in the crucible and thus provide a reducing atmosphere.

The crucible, containing the shell and lining material, is heated at a. temperaturev of about 1150 to 1170" centigrade for a length of time suflicient to melt the bronze, brass, or other copper alloy or mixture, and the crucible then turned slowly for a sufficient period of time to bring the molten brass, bronze or copper mixture in contact with the walls of the heated steel shell for an appreciable period of time, varying apcopper adhering to the surface of the copperiron alloy. The copper is found to have penetrated into the steel in somewhat the same manner as carbon in case-hardening processes. Afterwards, the crucible is removed from the furnace and agitated thoroughly by shaking, rolling, or otherwise, to mix the constituents of the brass, bronze, or lead copper mixture (which latter is a mechanical mixture and not a true alloy) to break up finely and thoroughly mix the various constituents of the mixture. In the case of crucibles in which the brass or bronze descends by gravity, the crucible subsequently is up-ended and plunged into water or other cooling medium so as to fix the brass or bronze and also to anneal the copper content; or in case the brass or bronze is to be centrifuged in place, the crucible is put in a centrifuging machine, and as soon as the mixture is centrifuged, the crucible is quickly chilled to prevent the heavy portions of the mixture being displaced and to anneal the copper constituent.

The main feature of my process is the soaking in Fig. 1.

I will explain the invention with reference to the accompanying drawing which illustrates several practical embodiments thereof to enable others familiar with the art to adopt and use the same; and will summarize in the claims the essential features of the invention, and novel features of construction for which protection is desired.

In said drawing:-

Fig. 1 is a vertical section through the crucible showing a steel shell-therein for coating both interiorly and exteriorly, and

Fig. 2 is a similar section through a modified crucible for coating a shell interiorly only.

In Figs. 1 and 2 the steel or other piece to be coated is designated by the reference character I, and is in the form of a tubular shell. The crucible within which the shell I to be coated is placed consists, in the case of Fig. 1, of an outer casing 2 and two ends 3 and l fitted on both the 7 tube I and on this casing 2. A central core 5 of suitable diameter likewise has its ends fitted in the ends 3 and 4. The end 4 is perforated with openings 6 forming the apertures for the escape of the air contained betweencasing 2 and shell I 'on the one hand, and between shell I and core 5 on the other hand. I designates the flux which is placed in thelower part of thecrucible; 8 represents the bronze, brass, or copper composition intended to form the exterior coating or lining and which fills the space between the outer casing 2 and the shell I, while 8' designates the bronze, brass or copper composition which may be the same as 8; or different, and which to form the interior lining of the shell is placed .in the space between tube I and core I.

In Fig. 2 the shell I is to be coated on its interior only, and the shell itself forms the outer casing of the crucible, In other respects the crucible in Fig. 2 does not difier from that shown In the case of shell to be coated on the exterior only use may also be made of the arrangement shown in Fig. 2, provided shell I is given the place of core 5.

In practical operation, the steel shell I to be coated is first placed in an acid bath in order to assure the removal of any crust, oxide scale or the like, and is then washed. At this stage of the treatment the shell I may be coated or I treated by sprinkling same with sal-ammoniac or other fiux, and then dried.

The shell I thus treated with the flux is then placed in the crucible, sumcient space being provided'between the walls of the crucible and the shell I which is to be coated with bronze, brass, or the like. In the case of Fig. l, clearance is provided between shell I, casing 2 and core 5,

while in the case of a shell to be coated only on its interior (as in Fig. 2) the shell I itself may serve as a crucible and it is necessary only to provide the core 5 and the end closure members 3-4. A small quantity of'sal-ammoniac or similar volatile flux I is then introduced into said spaces 88', although if the shell has not already been coated with flux this operation may be omitted. The remainder of the space is filled with a composition of bronze, brass, or lead copper, and the end members 3-4 of the crucible applied, the member 4 having only a small opening 6 directed into each space 8-8 containing the bronze, brass, or other composition.

The crucible is then placed in a furnace having a suitable temperature, ranging approximately from 1000 C., for certain bronzes, to 1200 C. for others depending upon the composition of the bronze used, and the crucible is allowed to remain until the bronze has been melted and has reached a temperature slightly above its melting point. When the crucible begins to heat, and before the bronze begins to fuse, the flux I vaporizes and evolves a'vapor or gas which forces.

the air from the crucible through the openings 6, the bronze or brass then being ready to fuse in an atmosphere which contains no oxygen.

After a temperature sensibly higher than the melting point of the brass or bronze has been reached, the crucible with the shell therein is turned slowly during or after the heating. for from 5 to 12 minutes so that the molten copper constituent will intimately contact the heated steel shell I, entering into the steel shell and forming a copper-iron or copper-steel alloy to which the copper oi the lining will readily bond. This soaking step is important in my process as it forms a coating of copper iron alloy bonded to the surface of the shell I, the copper-iron alloy having penetrated in somewhat the same manner as carbon in case-hardening processes. If the copperis not in intimate contact at the necessary temperature for the required time. necessary to form this alloy the bonding will be faulty, i. e. it is not deep enough. Hence I form a bearing surface of bronze or lead copper alloy firmly anchored to a ferrous or other backing or shell which alloy is not soldered but bonded to the shell by alloying a part of the copper form rolled or agitated so as to thoroughly admix the...

constituents of the bronze or brass, this being done up to the time at which the latter solidifies.

This operation not only admixes the bronze or brass in the neutral atmosphere of the crucible but it also assures perfect and complete uniting of the bronze or brass with the copper-iron alloy bonded to the iron or steel shell I.

when the bronze or brass has solidified the piece is allowed to cool slowly if a hard bronze or brass surface is desired; or if soft bronze or brass is desired the crucible is cooled quickly for the purpose ,of softening the copper which forms the lining. Hence in the case of tubular parts they can be put into a centrifuging machine and the metal centrifuged in place and the piece chilled in the machine. In this case the coating of copper on the steel deposited there during the soaking part of the process eliminates all danger of a bad bond, and any tendency to force lead towards the steel shell simply gives a mixture with a high lead content which is desirable for many after which the crucible is again sealed-and the process repeated, the high lead copper of the lining material (such as bronze) readily bonding to the prepared alloy surface. In every case it is necessary that the copper have a definite penetration into the steel to form a satisfactory bond.

It is to be understood that the invention is not limited to the consruction shown by way of example; andthe process may be applied to objects of all forms, hollow or otherwise. Moreover, the non-oxidizing medium or atmosphere 1.

1. In a method of making hearings or the like,

the step which consists in initially heating a lining material of copper alloy in intimate contact with a steel shell to a temperature higher than the melting point of the lining, and maintaining the contact at said temperature while rotating the shell for approximately five minutes to form a copper-iron alloy penetrating the surface of the shell and to whichthe main body of the molten lining material will readily bond.

2. The method of making hearings or the like which consists in providing a ferrous base and a quantity of copper alloy lining material in intimate contact; heating said base and lining material to a temperature above the melting point of the lining material; maintaining the molten lining material in contact with the heated base at said temperature for approximately flve minutes to permit the copper to soak into and form a copper-iron alloy at the surface of the base; applying the main body of the lining of copper alloy to the copper-iron alloy; and cooling said base to solidify the lining material.

3. The method of making hearings or the like which consists in providing a steel shell, introducing thereinto a quantity of copper alloy lining material; sealing the shell; heating said shell to a temperature above the melting point of the lining material; rotating the shell causing the molten lining to flow uniformly about the interior of the shell; maintaining the molten lining ma- I terial in intimate contact with. the heated shell at said temperature for approximately 5 minutes to permit the copper to soak into and form a copper-iron alloy penetrating the surface of the shell; agitating the shell to admix the constituents of the main body of the lining material, and cooling said shell to solidify the lining material.

4. The method of making hearings or the like, consisting in introducing into a ferrous shell, 8. non-oxidizing flux and copper alloy lining material; heating the shell and contents to a temperature above the melting point of the lining material and maintaining the molten lining material in intimate contact with the heated shell for approximately 5 minutes whereby a copperiron alloy is formed bonding the shell to the lining; and then cooling said shell and lining.

5. The method of making bearings, consisting in introducing a non-oxidizing flux and copper alloy lining material into a ferrous shell; heating the shell and contents to a temperature above the melting point of the lining material; rotating the shell to cause the molten lining to flow uniformly about the interior of the shell and maintaining the molten lining material in intimate contact with the heated shell tor approximately 5 minutes whereby a copper-iron alloy is formed bonding the shell to the lining; and then cooling said shell and lining.

HENRY LOWE BROWNBACK. 

